Under a White Sky: The Nature of the Future

One of the most-severe volcanic events ever recorded was the eruption of Mount Tambora, in Indonesia, in 1815. Tens of thousands of people died in the immediate aftermath of the explosion, but the effects were felt around the world for years, as particles and gases released by the eruption hung in the atmosphere. In 1816 in Europe and North America, harvests failed. Some estimates put the number of people who died of starvation in the millions.

The same phenomenon that caused catastrophe in the 19th century could be used to mitigate climate disaster in the 21st. Solar geoengineering involves putting reflective particles into the stratosphere, a layer of the atmosphere between eleven and six miles above the earth’s surface, to prevent sunlight from reaching the planet, which would prevent temperatures from rising. One of the researchers behind this approach, Frank Keutsch, initially thought the idea was misguided, but now believes that inaction on climate change, will make it necessary in the future.

One good candidate for reflective material is diamonds, which do not absorb energy and are unreactive. Another is sulfur dioxide, what volcanoes emit, but this could interfere with ozone levels and cause acid rain. The best option might be calcium carbonate, which makes up limestone and is common to many places on earth. Mathematical models show promise, “but until someone actually throws calcium carbonate into the stratosphere, it’s hard to know how much to trust the models” (172).

The first report to government about the phenomenon that would go on to be called global warming came out in 1965, during the presidency of Lyndon Johnson. The report suggested using reflective particles to control the climate, part of a weather-modification ethos that had taken hold at the time, with the US and USSR proposing various projects to control rainfall and increase temperatures at the poles. These projects fell out of favor in the 1970s, just as scientists warned that anthropogenic climate change would make climate modification necessary.

Now, a combination of cutting carbon emissions, capturing those emissions, and solar geoengineering may be necessary. Using geoengineering to cut warming by half would prevent the most extreme effects of climate change, could be relatively cheap to develop and deploy, and wouldn’t require very much time to have an effect. Nonetheless, it would only address the symptoms, not the underlying problem, and would require constant replenishment of particles, in increasing amounts, as temperatures continued to rise. Plus, there’s been considerable pushback to even small experiments designed to test the effects of spraying particles in the atmosphere, but even if carbon dioxide emissions were to stop immediately, widespread changes to the earth’s ecosystems are otherwise inescapable. Without artificial modification of the planet, ironically, many natural ecosystems are unlikely to survive. Nonetheless, the possible unintended consequences are much broader than those explored already in the book.

Project Iceworm was a 1960s US Army attempt to drill tunnels into Greenland’s ice sheet. To do so, the Army built Camp Century, a base on the ice sheet that had dorms, a mess hall, a chapel, and a portable nuclear reactor as a power source. However, the ceaseless movement of ice posed problems for the base, which had to undergo constant maintenance to prevent the structures from being crushed. The base closed in 1967, but while it was running, glaciologists drilled the first ice core samples out of the glacier: “what it revealed about the history of the climate was so puzzling and unlikely that scientists are still trying to make sense of it” (189).

Today, drilling operations continue at the North Greenland Ice Core Project. Danish researchers sink 12-foot drills through the ice, progressing through past layers of snow, which serve as time capsules from when they formed. Layers can show ash from volcanic eruptions, lead pollution and other relics from human activity, and information about the atmosphere. The first person to analyze ice cores in this way was Danish geophysicist Willi Dansgaard. In the 1960s, Dansgaard’s analysis of Greenland ice cores showed that in the past, temperatures fluctuated wildly; only in the past ten thousand years have temperatures stabilized—which is also the only period in which all human civilization has existed.

The reasons for the temperature swings before this point are still a mystery, but that the fact that the period of calm is coming to an end is clear; temperatures on the ice sheet have risen by three degrees Celsius since 1990, and the ice sheet is melting at a record pace. In the summer of 2019, it lost six hundred billion tons of ice. If the entire ice sheet were to melt, global sea levels would rise by 20 feet. Sea levels have risen significantly in the past, including when humans were on the planet, but modern cities are far less adaptable than the settlements of humans thousands of years ago. To counter the risks posed by melting ice sheets, officials and scientists have proposed everything from a series of artificial islands and retractable gates at the mouth of the New York Harbor, to a giant wall blocking the mouth of one of Greenland’s outlet glaciers: “First you speed up an ice stream; then you try to slow it down by erecting a three-hundred-foot-tall, three-mile-long concrete-topped embankment” (199).

None of the measures discussed in the book are improvements on nature—instead, they’re the best that humans can do, given the circumstances. The interventions are also risky: not only do they have to function, but they also need to be used by political actors in a responsible way.